Restraint assembly for cargo system

ABSTRACT

A restraint assembly includes a fitting base, a bushing, and a restraint roller disk, according to various embodiments. The fitting base includes a fitting lower surface and a fitting upper surface that is angled relative to the fitting lower surface, according to various embodiments. The fitting base may be configured to be coupled, via an anchor, to a rail upper surface of a guide rail of the cargo system. In various embodiments, the bushing is configured to be disposed about the anchor. In various embodiments, the restraint roller disk includes a roller upper surface and a roller lower surface, wherein the restraint roller disk is configured to be rotatably coupled about the bushing and the roller lower surface is configured to engage the fitting upper surface of the fitting base.

CROSS REFERENCE TO RELATED APPLICATION

This application is a divisional of, claims priority to and the benefitof, U.S. Ser. No. 15/903,792 filed on Feb. 23, 2018 and entitled“RESTRAINT ASSEMBLY FOR CARGO SYSTEM.” The '792 application is adivisional of, claims priority to and the benefit of, U.S. Pat. No.9,932,113 issued on Apr. 3, 2018 (aka U.S. Ser. No. 15/368,247 filed onDec. 2, 2016) and entitled “RESTRAINT ASSEMBLY FOR CARGO SYSTEM.” Bothof which are hereby incorporated by reference in their entirety for allpurposes.

FIELD

The present disclosure relates to cargo management systems, and morespecifically, to restraint assemblies for cargo management systems.

BACKGROUND

Conventional cargo systems typically include various tracks and rollers.For example, an aircraft cargo system may span a length of an aircraftand may be configured to load and unload aircraft cargo. Power driveunits (“PDUs”) convey cargo forward and aft along the aircraft onconveyance rollers which are attached to the aircraft floor structure.For example, cargo may be loaded from an aft position on an aircraft andconducted on a unit load device (“ULD”) or a pallet by the cargo systemto a forward position and/or, depending upon aircraft configuration,cargo may be loaded from a forward position on an aircraft and conductedby the cargo system to an aft position.

Conventional cargo systems are typically designed to vertically and/orlaterally restrain the cargo, ULD, and/or pallet as it moves along atrack. For example, conventional cargo restraining systems may include acontinuous vertical restraint lip that extends along a side of a track.However, such conventional restraining systems can be damaged by ULDfeatures and/or pallet tie-down fittings, among others. Additionally,conventional restraining systems may not provide sufficient verticalrestraint.

SUMMARY

In various embodiments, the present disclosure provides a restraintassembly of a cargo system. The restraint assembly includes a fittingbase, a bushing, and a restraint roller disk, according to variousembodiments. The fitting base includes a fitting lower surface and afitting upper surface that is angled relative to the fitting lowersurface, according to various embodiments. The fitting base may beconfigured to be coupled, via an anchor, to a rail upper surface of aguide rail of the cargo system. In various embodiments, the bushing isconfigured to be disposed about the anchor. In various embodiments, therestraint roller disk includes a roller upper surface and a roller lowersurface, wherein the restraint roller disk is configured to be rotatablycoupled about the bushing and the roller lower surface is configured toengage the fitting upper surface of the fitting base.

In various embodiments, an angle between the fitting lower surface andan axis of rotation of the restraint roller disk is between 5 degreesand 85 degrees. In various embodiments, the restraint roller disk isconfigured to extend in a lateral direction beyond a rail lateralsurface of the guide rail to engage and guide cargo. In variousembodiments, the roller lower surface is configured to directly engageand be in rotating-sliding contact with the fitting upper surface of thefitting base. The roller upper surface and the roller lower surface ofthe restraint roller disk may be substantially parallel to each other.For example, the restraint roller disk may include a radially outwardedge portion and the radially outward edge portion may have afrustoconical tapered surface extending at least partially between theroller upper surface and the roller lower surface.

Also disclosed herein, according to various embodiments, is a cargosystem that includes a guide rail and a restraint assembly. The guiderail may include a rail upper surface and a rail lateral surface. Therestraint assembly may include a restraint roller disk rotatably coupledto the rail upper surface of the guide rail, wherein the restraintroller disk is disposed in an angled orientation relative to the raillateral surface.

In various embodiments, an angle between the rail lateral surface and anaxis of rotation of the restraint roller disk is between 5 degrees and85 degrees. In various embodiments, the restraint roller disk extends ina lateral direction beyond the rail lateral surface of the guide rail toengage and guide at least one of cargo and a cargo shuttle. Therestraint assembly may further include an anchor, a fitting base, and abushing. The fitting base may include a fitting lower surface and afitting upper surface that is angled relative to the fitting lowersurface, wherein the fitting base is coupled, via the anchor, to therail upper surface of the guide rail. The bushing may be disposed aboutthe anchor, wherein the restraint roller disk is rotatably coupled aboutthe bushing.

The bushing may include a bushing upper surface that is perpendicularwith a longitudinal axis of the anchor for engaging at least one of ahead and a washer of the anchor. For example, the bushing upper surface,the fitting lower surface, and the rail upper surface may be parallel toeach other and may be perpendicular to the rail lateral surface. Invarious embodiments, the restraint roller disk includes a roller uppersurface and a roller lower surface, wherein the roller lower surfaceengages the fitting upper surface of the fitting base.

In various embodiments, the roller lower surface is in rotating-slidingcontact with the fitting upper surface of the fitting base. In variousembodiments, the roller upper surface and the roller lower surface ofthe restraint roller disk are substantially parallel to each other. Invarious embodiments, the restraint roller disk has a radially outwardedge portion that has a frustoconical tapered surface extending at leastpartially between the roller upper surface and the roller lower surface.In various embodiments, a segment of the frustoconical tapered surfaceis substantially parallel with the fitting lower surface and the railupper surface. In various embodiments, the segment of the frustoconicaltapered surface is disposed lower than the fitting lower surface and therail upper surface. The restraint roller disk may be made from ametallic material.

Also disclosed herein, according to various embodiments, is a method forrestraining a cargo shuttle. The method may include moving the cargoshuttle along a track of a cargo system and utilizing a restraint rollerdisk to vertically restrain the cargo shuttle as it moves along thetrack of the cargo system. An angle between an axis of rotation of therestraint roller disk and the track of the cargo system may be between 5degrees and 85 degrees.

The forgoing features and elements may be combined in variouscombinations without exclusivity, unless expressly indicated hereinotherwise. These features and elements as well as the operation of thedisclosed embodiments will become more apparent in light of thefollowing description and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B illustrate a cargo system of an aircraft, in accordancewith various embodiments;

FIGS. 2A and 2B illustrate perspective views of a restraint assembly ofa cargo system, in accordance with various embodiments;

FIG. 3 illustrates a perspective cross-sectional view of a restraintassembly of a cargo system, in accordance with various embodiments;

FIG. 4 illustrates a cross-sectional view of the restraint assembly ofFIG. 3, in accordance with various embodiments;

FIG. 5 illustrates a perspective view of a restraint assembly of a cargosystem, in accordance with various embodiments; and

FIG. 6 is a schematic flow chart diagram of a method of restraining acargo shuttle, in accordance with various embodiments.

The subject matter of the present disclosure is particularly pointed outand distinctly claimed in the concluding portion of the specification. Amore complete understanding of the present disclosure, however, may bestbe obtained by referring to the detailed description and claims whenconsidered in connection with the drawing figures.

DETAILED DESCRIPTION

The detailed description of exemplary embodiments herein makes referenceto the accompanying drawings, which show exemplary embodiments by way ofillustration. While these exemplary embodiments are described insufficient detail to enable those skilled in the art to practice thedisclosure, it should be understood that other embodiments may berealized and that logical changes and adaptations in design andconstruction may be made in accordance with this disclosure and theteachings herein without departing from the spirit and scope of thedisclosure. Thus, the detailed description herein is presented forpurposes of illustration only and not of limitation.

As used herein, “aft” refers to the direction associated with the tailof an aircraft, or generally, to the direction of exhaust of the gasturbine. As used herein, “forward” refers to the direction associatedwith the nose of an aircraft, or generally, to the direction of flightor motion.

Cargo management systems, as disclosed herein, are used to load, move,and unload cargo. While numerous examples and details are included belowwith reference to aircraft cargo systems, it is expected that thepresent disclosure may apply to other, non-aircraft type cargo systems.

FIG. 1A illustrates an underside of an aircraft 25 and FIG. 2Aillustrates an aircraft cargo deck 29 that can be used to implementvarious embodiments of the present disclosure. A generally H-shapedconveyance surface 26 forms a deck of an aircraft, adjacent a cargo bayloading door 23. However, there are many other aircraft cargo deckconfigurations to which the embodiments of the disclosure can beimplemented. For example, various aircraft, particularly thoseconfigured primarily for the transportation of cargo without passengers,have the upper passenger deck removed and an additional larger cargodeck installed. Other aircraft may have three or more parallellongitudinal tracks rather than the H-shape shown in FIG. 1B.

The cargo compartment includes a cargo loading system comprising aplurality of freely rotating conveyance rollers 27 mounted in the cargodeck to define the conveyance plane. Cargo loaded onto the aircraftcargo deck can be moved manually throughout the cargo bay upon thefreely rotating conveyance rollers. However, it is desirable toelectro-mechanically propel the cargo with minimal or no manualassistance. In that regard, the H-shaped cargo surface includes a numberof PDUs 28 that provide a mechanism upon which cargo is propelled overthe conveyance rollers 27. Each PDU 28 typically includes a drive rollerelement which can be raised from a lowered position beneath the cargodeck to an elevated position. These PDUs are referred to as “self-lift”PDUs. In the elevated position, the drive roller element contacts anddrives the overlying cargo that rides on the conveyance rollers. Othertypes of PDUs, which can also be used as embodiments of the presentdisclosure, are above the conveyor plane all the time and held up by aspring. These PDUs are referred to as “spring-lift” PDUs.

In the longitudinal direction, the H-shaped conveyance surface 26includes a left track and a right track along which cargo is to bestowed in parallel columns during flight. In the transverse direction,the cargo deck is also separated into a tail (or “aft”) section 11 and aforward section 12. Thus, the left and right tracks are divided intofour sections, two forward sections 13 and 15 and two aft sections 17and 19. In addition to the four sections, there is an additional path 21between both tracks at the cargo bay loading door 23. This additionalpath 21 divides the cargo bay between the forward section 12 and aftsection 11. This path is used to move cargo into and out the aircraft,and also to transfer cargo between the left and right storage tracks.

In one embodiment, a human operator manipulates control elements toselectively and electrically energize PDUs 28 in each of the fiveaforementioned sections 13, 15, 17, 19 and 21. Typically, these controlsare mounted in an operator interface unit. The control elements may bemounted on a wall or other structure within the cargo bay or may beportable, e.g., the controls may be in a hand held pendant. Thesecontrols will typically have an on/off switch and a joystick which,depending on the direction pushed, will energize a set of PDUs 28,causing groups of drive roller elements to be elevated (if not alreadyelevated) and rotated in one of two possible directions (i.e., forwardor reverse). A section of PDUs will remain energized as long as thejoystick is held in a corresponding position. In response to release ofthe joystick, the selected set of PDUs is de-energized. In the case ofself-lifting PDUs, the drive roller elements are returned to theirretracted position below the plane of the conveyance rollers 27; in thecase of spring-lift PDUs, the PDUs remain biased in the upward positionand brakes are applied to hold the cargo containers in place.

The cargo system 100 may include one or more cargo shuttles that areconfigured to slide across floor panels or roll across the conveyancerollers 27. The cargo shuttles may be unit load devices (“ULD”),pallets, or other components on which cargo may be secured. In variousembodiments, the cargo system 100 includes guide rails that areconfigured to guide the cargo shuttles. For example, guide rails may bedisposed along the aforementioned sections of the conveyance surface 26and/or may be disposed along the cargo tracks to restrict and restrainthe movement of the cargo shuttles. The guide rails may becoupled/mounted to an airframe of the aircraft. In various embodiments,one or more restraint assemblies 400 (with reference to FIGS. 2A and 2B)are coupled to the guide rails to facilitate vertical restraint (z axis)and lateral restraint (x axis) of the cargo shuttles along and acrossthe conveyance surface 26.

With continued reference to FIGS. 2A and 2B, the restraint assembly 400generally includes a restraint roller disk 410 that is rotatably coupledto the guide rail 222. In various embodiments, the guide rail 222includes a rail upper surface 223 and a rail lateral surface 225. Therestraint roller disk 410 may be coupled to the rail upper surface 223of the guide rail 222 and the restraint roller disk 410 may be disposedin an angled orientation relative to the rail lateral surface 225. Therestraint roller disk 410 may be made from a metallic material, amongothers. For example, the restraint roller disk 410 may be made fromsteel, aluminum, or alloys thereof.

In various embodiments, an angle between the rail lateral surface 225(which is parallel to the z axis) and an axis of rotation 419 (withmomentary reference to FIG. 4) of the restraint roller disk 410 isbetween 1 degree and 89 degrees. In other words, and according tovarious embodiments, the restraint roller disk 410 does not rotate abouta horizontal axis (x axis or y axis) nor a vertical axis (z axis), butinstead rotates about an oblique axis 419. In various embodiments, theangle between the rail lateral surface 225 and the axis of rotation 419(with momentary reference to FIG. 4) is between 5 degrees and 85degrees. In various embodiments, the angle between the rail lateralsurface 225 and the axis of rotation 419 (with momentary reference toFIG. 4) is between 10 degrees and 80 degrees.

As described in greater detail below, the restraint assembly 400 mayalso include an anchor 405, a fitting base 420 coupled/mounted to theairframe 110 of the aircraft, and a bushing 430 that is disposed aboutthe anchor 405. Also, as described in greater detail below, the angledorientation of the restraint roller disk 410 of the restraint assembly400 generally provides vertical restraint to lips/edges of cargoshuttles while also preventing protruding features 515 of the cargoshuttle 514 (with momentary reference to FIG. 5) from being hindered orcaught on the restraint assembly 400. In other words, the restraintroller disk extends in a lateral direction (x axis) beyond the raillateral surface 225 to engage and guide the cargo or the cargo shuttle114. Accordingly, the angled orientation of the restraint roller disk410 together with the rotatable configuration of the restraint rollerdisk 410 generally improves operation of the cargo system 100 and/orprevents damage to the cargo system 100.

In various embodiments, the fitting base 420 may be disposed between therestraint roller disk 410 and the guide rail 222. In variousembodiments, the fitting base 420 is a portion of the airframe 110 ofthe aircraft. In various embodiments, the fitting base 420 is a separatecomponent from the airframe 110. The fitting base 420 may include afitting lower surface 424 that is coupled to and in contact with therail upper surface 223 of the guide rail 222. The fitting base 420 mayalso include a fitting upper surface 422 that is angled relative to thefitting lower surface 424 and thus imparts, at least partially, theangled orientation to the restraint roller disk 410. In other words, thefitting upper surface 422 of the fitting base 420 may directly engageand be in rotating-sliding contact with a roller lower surface 414 ofthe restraint roller disk 410 to support rotation of the restraintroller disk 410 about the axis of rotation 419 in the angledorientation.

In various embodiments, and with reference to FIGS. 3 and 4, therestraint roller disk 410 is rotatably disposed about the bushing 430,which is disposed about the anchor 405. The restraint roller disk 410can rotate about the bushing 430 in response to cargo and/or the cargoshuttle 114 contacting the restraint roller disk 410 as the cargo and/orcargo shuttle 114 moves along a track of the cargo system 100. Invarious embodiments, the bushing 430 is non-rotatably coupled/attachedto the anchor 405. In various embodiments, the bushing 430 has a bushingupper surface 432 that is perpendicular with a longitudinal axis 409 ofthe anchor 405. The bushing upper surface 432 may provide a surfaceagainst which a head 407 of the anchor 405 (or a washer/nut of theanchor) may be seated for mounting the restraint assembly 400 to theguide rail 222 and/or airframe 110 of the aircraft.

In various embodiments, the bushing upper surface 432 of the bushing430, the fitting lower surface 424 of the fitting base 420, and the railupper surface 223 of the guide rail 222 are parallel to each other andare perpendicular to the rail lateral surface 225 of the guide rail 222.In various embodiments, the roller upper surface 412 and the rollerlower surface 414 of the restraint roller disk 410 are substantiallyparallel to each other. In such embodiments, the angled orientation ofthe restraint roller disk 410 is generally the same as the angledorientation between the fitting upper surface 422 and the fitting lowersurface 424.

In various embodiments, a radially outward edge portion of the restraintroller disk 410 has a frustoconical tapered surface 413 that extends atleast partially between the roller upper surface 412 and the rollerlower surface 414. This frustoconical tapered surface 413 may facilitateimproved engagement with the cargo shuttle 114. For example, a segmentof the frustoconical tapered surface 413 may be substantially parallelwith a lip 113 of the cargo shuttle 114 (and parallel with the fittinglower surface 424 and the rail upper surface 223) and thus mayfacilitate a secure vertical restraint of the cargo shuttle 114. WhileFIG. 4 shows a gap between the lip 113 of the cargo shuttle 114 and therestraint roller disk 410, during operation of the cargo system 100 thecargo shuttle may be susceptible to vertical movement. Accordingly, ifthe lip 113 of the cargo shuttle 114 is higher than the rail uppersurface 223 of the guide rail 222, as the cargo shuttle 114 approachesthe restraint assembly 400 the lip 113 may engage the restraint rollerdisk 410. As the cargo shuttle 114 continues to move along the track,the restraint roller disk 410 rotates and guides the lip 113 downwardsvertically restrain the cargo shuttle 114. In various embodiments, thesegment of the frustoconical tapered surface 413 is disposed lower thanthe fitting lower surface 424 of the fitting base 420 and the rail uppersurface 223 of the guide rail 222.

In various embodiments, and with reference to FIG. 5, the restraintroller disk 410 may be configured to provide a degree of lateralrestraint by laterally guiding features 515 protruding from the cargoshuttle 514. For example, the cargo shuttle 514 may be a pallet and oneor more fasteners, straps, tie-downs, etc., may extend from the pallet.The restraint assembly 400 may prevent such features 515 from becomingcaught or snagged during movement of the cargo shuttle 514 along thecargo system. In other words, the restraint roller disk 410 may, inaddition to the vertical restraint described above, provide lateralrestraint to the cargo shuttle 514 and thus may prolong the operationallife of the cargo system 100 and/or prevent damage to cargo.

In various embodiments, and with reference to FIG. 6, a method 690 forrestraining a cargo shuttle is provided. The method 690 includes movingthe cargo shuttle along a track of the cargo system at step 692 andutilizing a restraint roller disk to vertically restrain the cargoshuttle at step 694. In various embodiments an angle between an axis ofrotation of the restraint roller disk and the track of the cargo systemis between 1 degree and 89 degrees. In various embodiments, the anglebetween the axis of rotation of the restraint roller disk and the trackof the cargo system is between 5 degrees and 85 degrees. In variousembodiments, the angle between the axis of rotation of the restraintroller disk and the track of the cargo system is between 10 degrees and80 degrees.

Benefits, other advantages, and solutions to problems have beendescribed herein with regard to specific embodiments. Furthermore, theconnecting lines shown in the various figures contained herein areintended to represent exemplary functional relationships and/or physicalcouplings between the various elements. It should be noted that manyalternative or additional functional relationships or physicalconnections may be present in a practical system. However, the benefits,advantages, solutions to problems, and any elements that may cause anybenefit, advantage, or solution to occur or become more pronounced arenot to be construed as critical, required, or essential features orelements of the disclosure.

The scope of the disclosure is accordingly to be limited by nothingother than the appended claims, in which reference to an element in thesingular is not intended to mean “one and only one” unless explicitly sostated, but rather “one or more.” It is to be understood that unlessspecifically stated otherwise, references to “a,” “an,” and/or “the” mayinclude one or more than one and that reference to an item in thesingular may also include the item in the plural. All ranges and ratiolimits disclosed herein may be combined.

Moreover, where a phrase similar to “at least one of A, B, or C” is usedin the claims, it is intended that the phrase be interpreted to meanthat A alone may be present in an embodiment, B alone may be present inan embodiment, C alone may be present in an embodiment, or that anycombination of the elements A, B and C may be present in a singleembodiment; for example, A and B, A and C, B and C, or A and B and C.Different cross-hatching is used throughout the figures to denotedifferent parts but not necessarily to denote the same or differentmaterials.

The steps recited in any of the method or process descriptions may beexecuted in any order and are not necessarily limited to the orderpresented. Furthermore, any reference to singular includes pluralembodiments, and any reference to more than one component or step mayinclude a singular embodiment or step. Elements and steps in the figuresare illustrated for simplicity and clarity and have not necessarily beenrendered according to any particular sequence. For example, steps thatmay be performed concurrently or in different order are illustrated inthe figures to help to improve understanding of embodiments of thepresent disclosure.

Any reference to attached, fixed, connected or the like may includepermanent, removable, temporary, partial, full and/or any other possibleattachment option. Additionally, any reference to without contact (orsimilar phrases) may also include reduced contact or minimal contact.Surface shading lines may be used throughout the figures to denotedifferent parts or areas but not necessarily to denote the same ordifferent materials. In some cases, reference coordinates may bespecific to each figure.

Systems, methods and apparatus are provided herein. In the detaileddescription herein, references to “one embodiment”, “an embodiment”,“various embodiments”, etc., indicate that the embodiment described mayinclude a particular feature, structure, or characteristic, but everyembodiment may not necessarily include the particular feature,structure, or characteristic. Moreover, such phrases are not necessarilyreferring to the same embodiment. Further, when a particular feature,structure, or characteristic is described in connection with anembodiment, it is submitted that it is within the knowledge of oneskilled in the art to affect such feature, structure, or characteristicin connection with other embodiments whether or not explicitlydescribed. After reading the description, it will be apparent to oneskilled in the relevant art(s) how to implement the disclosure inalternative embodiments.

Furthermore, no element, component, or method step in the presentdisclosure is intended to be dedicated to the public regardless ofwhether the element, component, or method step is explicitly recited inthe claims. No claim element is intended to invoke 35 U.S.C. 112(f)unless the element is expressly recited using the phrase “means for.” Asused herein, the terms “comprises”, “comprising”, or any other variationthereof, are intended to cover a non-exclusive inclusion, such that aprocess, method, article, or apparatus that comprises a list of elementsdoes not include only those elements but may include other elements notexpressly listed or inherent to such process, method, article, orapparatus.

What is claimed is:
 1. A method for restraining a cargo shuttle, themethod comprising: moving the cargo shuttle along a track of a cargosystem; and utilizing a restraint roller disk to vertically restrain thecargo shuttle as it moves along the track of the cargo system, whereinan angle between an axis of rotation of the restraint roller disk andthe track of the cargo system is between 5 degrees and 85 degrees. 2.The method of claim 1, wherein the cargo system comprises: a guide railcomprising a rail upper surface and a rail lateral surface; a restraintassembly comprising the restraint roller disk rotatably coupled to therail upper surface of the guide rail; an anchor; a fitting basecomprising a fitting lower surface and a fitting upper surface that isangled relative to the fitting lower surface, wherein the fitting baseis coupled, via the anchor, to the rail upper surface of the guide rail;and a bushing disposed about the anchor, wherein the restraint rollerdisk is rotatably coupled about the bushing.
 3. The method of claim 2,wherein the restraint roller disk extends in a lateral direction beyondthe rail lateral surface of the guide rail to engage and guide at leastone of cargo and a cargo shuttle.
 4. The method of claim 2, wherein thebushing comprises a bushing upper surface that is perpendicular with alongitudinal axis of the anchor for engaging at least one of a head anda washer of the anchor.
 5. The method of claim 14, wherein the bushingupper surface, the fitting lower surface, and the rail upper surface areparallel to each other and are perpendicular to the rail lateralsurface.
 6. The method of claim 2, wherein the restraint roller diskcomprises a roller upper surface and a roller lower surface, wherein theroller lower surface engages the fitting upper surface of the fittingbase.
 7. The method of claim 6, wherein the roller lower surface is inrotating-sliding contact with the fitting upper surface of the fittingbase.
 8. The method of claim 6, wherein the roller upper surface and theroller lower surface of the restraint roller disk are substantiallyparallel to each other.
 9. The method of claim 8, wherein the restraintroller disk comprises a radially outward edge portion, wherein theradially outward edge portion comprises a frustoconical tapered surfaceextending at least partially between the roller upper surface and theroller lower surface.
 10. The method of claim 9, wherein a segment ofthe frustoconical tapered surface is substantially parallel with thefitting lower surface and the rail upper surface.
 11. The method ofclaim 10, wherein the segment of the frustoconical tapered surface isdisposed lower than the fitting lower surface and the rail uppersurface.
 12. The method of claim 2, wherein the restraint roller disk ismade from a metallic material.
 13. The method of claim 2, wherein theangle is between the axis of rotation of the restraint roller disk andthe fitting lower surface.
 14. The method of claim 6, wherein the rollerlower surface is configured to directly engage and be inrotating-sliding contact with the fitting upper surface of the fittingbase.
 15. The method of claim 14, wherein the roller upper surface andthe roller lower surface of the restraint roller disk are substantiallyparallel to each other.
 16. The method of claim 15, wherein therestraint roller disk comprises a radially outward edge portion, whereinthe radially outward edge portion comprises a frustoconical taperedsurface extending at least partially between the roller upper surfaceand the roller lower surface.